The present invention relates to a vehicle blower motor device and a holder for the blower motor device.
A typical blower motor device used in a vehicle air conditioning system has a direct-current motor as a power source. Since the blower motor device is continuously driven at a high power, friction between brushes and a commutator produces heat. This increases the temperature of the motor particularly at the brushes and the commutator. Therefore, to improve the quality of the motor, it is important to design the motor to suppress the temperature increase of the motor.
Japanese Laid-Open Patent Publication No. 2002-204547 discloses a blower motor device that has an air duct for taking cooling air to the interior of a motor. The air duct connects an inlet formed at a predetermined position in the blower motor device to the interior of the motor, and guides air taken at the inlet to the interior of the motor.
However, the inlet of the blower motor of the publication is opened to a side of the device and therefore cannot guide air to the interior of the motor to sufficiently cool the motor. To sufficiently cool the motor, the device may be configured as shown in FIG. 5 such that rotation of the motor, specifically rotation of a rotor attached to an output shaft of the motor, may be used to take cooling air into the interior of the motor.
That is, a motor holder 71 of a blower motor device shown in FIG. 5 holds a motor (not shown) located to the right as viewed in FIG. 5. The motor holder 71 includes a substantially circular coupling member 72 attached to a vehicle and a cover plate 73 attached to the lower side of the coupling member 72. The coupling member 72 and the cover plate 73 define an air duct 76 for guiding cooling air toward the motor. The coupling member 72 includes an inlet cylinder 75 that forms an inlet 74. The inlet cylinder 75 extends upward from the coupling member 72. The inlet 74 connects an exterior space above the motor holder 71 with the air duct 76. When rotated by the motor, a fan creates an air flow from the inlet 74 to the motor via the air duct 76 to cool the motor.
Droplets of, for example, car wash liquid, collect on the inner surface of the inlet cylinder 75. Collected droplets move along the inner surface of the inlet cylinder 75 and the inner surface of the air duct 76, and reach a boundary 77 between the coupling member 72 and the cover plate 73. Since a slight space exists at the boundary 77 between the coupling member 72 and the cover plate 73, droplets ooze out from the motor holder 71 through the boundary 77 due to a capillary phenomenon. The droplets are than sent to the passenger compartment by the air flow produced by rotation of the fan.
If air rushes in through the inlet 74, the air flow causes droplets to reach the interior of the motor. This causes the motor to malfunction.
A blower motor device disclosed in Japanese Laid-Open Patent Publication No. 2000-316247 also has an air duct for motor cooling air. The blower motor device of the publication includes a lower case attached to a motor holder. The lower case accommodates a control circuit for controlling a motor. A notch or a projection is formed at a boundary between the motor holder and the lower case. If droplets that entered the air duct reach the boundary between the motor holder and the lower case, the droplets move along the boundary. At this time, the notch or the projection blocks the droplets moving toward the control circuit along the boundary, thereby preventing the control circuit from being wet.
However, the device of the publication No. 2000-316247 allows droplets to reach the boundary between the motor holder and the lower case, and does not prevent droplets from reaching the boundary. Therefore, the device cannot eliminate the drawbacks presented by the device of FIG. 5. Also, since droplets are permitted to reach the boundary between the motor holder and the lower case, there is a possibility that droplets reach the control circuit.
Accordingly, it is an objective of the present invention to provide a vehicle blower motor device and a holder for the blower motor device that have an improved water resistance.
To achieve the foregoing and other objectives and in accordance with the purpose of the present invention, a vehicle blower motor device having a motor and a holder is provided. The holder includes a holder body, a flange, and a cover plate. The holder body accommodates and holds the motor. The flange extends radially outward from the holder body. The cover plate is attached to the flange and the holder body such that the cover plate is located below the flange. A first boundary is formed between the cover plate and the flange, and a second boundary is formed between the cover plate and the holder body. The holder body, the flange, and the cover plate define an air duct. The flange has an inlet. The inlet connects the air duct, which is located below the flange, with an outside space that is located above the flange. Air is guided from the inlet to the interior of the holder body through the air duct to cool the motor. A blocking portion is provided in the air duct and between the inlet and the first boundary. The blocking portion prevents liquid collected on the inlet from reaching the first boundary.
The present invention may also be applied to a holder in a vehicle blower motor device having a holder body, a flange, a cover plate, an air duct, and a blocking portion. The holder body accommodates and holds a motor. The flange extends radially outward from the holder body. The cover plate is attached to the flange and the holder body such that the cover plate is located below the flange. A first boundary is formed between the cover plate and the flange, and a second boundary is formed between the cover plate and the holder body. The air duct is defined by the holder body, the flange, and the cover plate. The flange has an inlet. The inlet connects the air duct, which is located below the flange, with an outside space that is located above the flange. Air is guided from the inlet to the interior of the holder body through the air duct to cool the motor. The blocking portion is provided in the air duct and between the inlet and the first boundary. The blocking portion prevents liquid collected on the inlet from reaching the first boundary.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.